His visit to the Serbian capital is the first since July's arrest in Belgrade of former Bosnian Serb leader Radovan Karadzic and his transfer to The Hague, a breakthrough in Serbia's cooperation with the tribunal.

Serbian authorities hope Brammertz will inform the European Union their country is now fully cooperating with The Hague court. This would pave the way for implementation of the agreement on closer EU-Serbian ties lawmakers in Belgrade approved Tuesday.

EU officials are to meet next week to consider the issue.

Karadzic and Mladic face charges stemming from the shelling and sniping that terrorized civilians in Bosnia-Herzegovina's capital Sarajevo in the 1990s. They also were involved in the 1995 massacre of an estimated 8,000 Muslim men and boys near Srebrenica.

Hadzic is charged with running a "joint criminal enterprise" aimed at expelling ethnic Croats from Serb-held areas of Croatia.